System and method and apparatus for a continuous aerosol monitor (CAM) using electro-optical weighing for general aerosols

Claim 3

A method as set forth in claim 1 wherein said convection currents are caused to occur by heating the representative sample of air.

Claim 4

A method as set forth in claim 1 wherein said step of drawing a sample of air includes restricting the flow of air across a predetermined cross sectional area defined in a plane normal to the direction of air flow and parallel to the beam.

Claim 5

A method as set forth in claim 1 wherein said step of drawing a representative sample of air includes simultaneously dessicating the sample of air.

Claim 6

A method as set forth in claim 1 wherein said beam of radiation has a diameter which is less than the product of the velocity of the sample of air drawn across the sampling volume and the predetermined sampling interval.

Claim 7

A method as set forth in claim 1 further including the step of establishing a process zero baseline for calibration of the measurement apparatus.

Claim 8

A method as set forth in claim 6 wherein said process zero is established by passing particle-free fluid through the sampling volume.

Claim 9

Electro-optical apparatus for providing in situ measurements of the mass concentration of particulates entrained in air comprising an electro-optical assembly including a source of substantially monchromatic electromagnetic radiation, optical means for directing a beam of said radiation through a sampling volume for impingement upon particulates contained therein whose mass concentration is to be measured, and receiver optics including photo detector means responsive to said radiation for developing an analog signal representative of radiation directed onto said detector means and indicative of the mass concentration of particulates in the sampling volume and optical means for collecting and directing radiation from said sampling volume traversed by said beam onto said photo detector, said sampling volume being defined by the interception of the beam of radiation by the projected acceptance geometry of the receiver optics, and a preseparator for drawing a representative sample of air across said sampling volume, said preseparator having an air flow channel open to the air at one end and a second end in communication with said sampling volume.

Claim 10

Electro-optical apparatus for providing in situ measurements of the mass concentration of particulates entrained in air comprising an electro-optical assembly including a source of substantially monchromatic electromagnetic radiation, optical means for directing a beam of said radiation through a sampling volume for impingement upon particulates contained therein whose mass concentration is to be measured, and receiver optics including photo detector means responsive to said radiation for developing an analog signal representative of radiation directed onto said detector means and indicative of the mass concentration of particulates in the sampling volume and optical means for collecting and directing radiation from said sampling volume traversed by said beam onto said photo detector, said sampling volume being defined by the interception of the beam of radiation by the projected acceptance geometry of the receiver optics, and a preseparator for drawing a representative sample of air across said sampling volume, said preseparator having an air flow channel open to the air at one end and a second end in communication with said sampling volume.

Claim 11

Apparatus as set forth in claim 8 wherein said preseparator is a vertical elutriator having said flow channel vertically disposed and said apparatus further includes a flow cell having a second cross channel normal to said first channel and in communication therewith, said optical assembly being disposed in said cross channel.

Claim 12

A system as set forth in claim 9 further including means collected to said detector means for classifying said analog signal according to whether small or large particulates are detected in the sampling volume and developing a classification signal in response thereto, means for subclassifying said classification signal according to the size thereof and developing an output in response thereto and means for operating on said output to develop a read out of the mass concentration of the particulates in the sampling volume.

Claim 13

Apparatus as set forth in claim 8 wherein said preseparator includes heater means for causing said air flow to occur through said preseparator by convection currents.

Claim 14

Apparatus as set forth in claim 8 including a flow cell disposed in said preseparator, said channel being defined at one end of said flow cell by an internal concave surface extending toward said sampling volume and terminating thereat in a restricted orifice.

Claim 15

A system as set forth in claim 8 further including means connected to said detector means for classifying said analog signal according to whether small or large particulates are detected in the sampling volume and developing a classification signal in response thereto, means for sub-classifying said classification signal according to the size thereof and developing an output in response thereto and means for operating on said output to develop a read out of the mass concentration of the particulates in the sampling volume.

Claim 16

A system as set forth in claim 13 wherein said preseparator for drawing air includes a flow cell arranged to restrict the flow of air to a predetermined region, said flow cell having a restricted opening of predetermined cross sectional area defined in a plane normal to the direction of air flow.

Claim 17

An electro-optical system for electro-optically weighing, in situ, particulates entrained in air comprising means for producing a beam of substantially monochromatic electromagnetic radiation, a sampling volume disposed between said means for producing said beam of radiation and receiver optics means having a radiation acceptance geometry and having a major axis along said beam, means for directing said beam of radiation through said sampling volume where it may impinge upon an object whose properties are to be measured, means for drawing a representative sample of ambient air containing the particulates to be weighed in a path crossing and normal to the major axis of the sampling volume in a predetermined interval of time having a duration such that no particle is sampled twice or more during the predetermined interval, said receiver optics means including detector means for developing an analog signal related to the intensity of radiation directed onto said detector means and optical means for collecting and focusing onto said detector means radiation scattered from said sampling volume traversed by said beam and periodically blocking said beam and redirecting a predetermined fraction of said beam onto said optical means and for periodically interrupting said scattered radiation such that said analog signal includes a plurality of time varying signal components including a calibration signal component, a zero signal component and a means connected to said detector for processing said analog signal to develop an output signal corresponding to the mass concentration of the particulates in the sampling volume.

Claim 18

An electro-optical system for electro-optically weighing, in situ, particulates entrained in air comprising means for producing a beam of substantially monochromatic electromagnetic radiation, a sampling volume disposed between said means for producing said beam of radiation and receiver optics means having a radiation acceptance geometry and having a major axis along said beam, means for directing said beam of radiation through said sampling volume where it may impinge upon an object whose properties are to be measured, means for drawing a representative sample of ambient air containing the particulates to be weighed in a path crossing and normal to the major axis of the sampling volume in a predetermined interval of time having a duration such that no particle is sampled twice or more during the predetermined interval, said receiver optics means including detector means for developing an analog signal related to the intensity of radiation directed onto said detector means and optical means for collecting and focusing onto said detector means radiation scattered from said sampling volume traversed by said beam and periodically blocking said beam and redirecting a predetermined fraction of said beam onto said optical means and for periodically interrupting said scattered radiation such that said analog signal includes a plurality of time varying signal components including a calibration signal component, a zero signal component and a means connected to said detector for processing said analog signal to develop an output signal corresponding to the mass concentration of the particulates in the sampling volume.

Claim 19

A system as set forth in claim 15 wherein said means connected to said detector includes means for classifying said analog signal according to whether small or large particulates are detected in the sampling volume and developing a classification signal in response thereto, means for sub-classifying said classification signal according to the size thereof and developing an output signal in response thereto and means for operating on said output signal to develop a read out of the mass concentration of the particulates in the sampling volume.

Claim 21

An electro-optical system for electro-optically weighing, in situ, particulates entrained in ambient air comprising means for producing a beam of substantially monochromatic electromagnetic radiation, a sampling volume disposed between said means for producing said beam of radiation and receiver optics means having a radiation acceptance geometry whose projection intercepts said beam of radiation, said sampling volume being defined by the interception of said beam of radiation by said projected acceptance geometry and having a major axis along said beam, means for directing said beam of said radiation through said sampling volume where it may impinge upon an object whose properties are to be measured, preseparator means for drawing a representative sample of ambient air containing the particulates to be weighed in a path crossing and normal to the major axis of the sampling volume, said receiver optics means including detector means for developing an analog signal related to the intensity of radiation directed onto said detector means and optical means for collecting and focusing onto said detector means radiation scattered from said sampling volume traversed by said beam and calibration/zero control means disposed between said sampling volume and the receiver optics means for periodically blocking said beam and redirecting a predetermined fraction of said beam onto said optical means and for periodically interrupting said scattered radiation such that said analog signal includes a plurality of time varying signal components including a calibration signal component, a zero signal component and a measurement signal component, means for processing said analog signal to develop individual control signals corresponding to said signal components for providing automatic compensation of the electro-optical system and means responsive to said analog signal for developing read out information corresponding to the mass concentration of the particulates in the sampling volume.

Claim 22

An electro-optical system for electro-optically weighing, in situ, particulates entrained in ambient air comprising means for producing a beam of substantially monochromatic electromagnetic radiation, a sampling volume disposed between said means for producing said beam of radiation and receiver optics means having a radiation acceptance geometry whose projection intercepts said beam of radiation, said sampling volume being defined by the interception of said beam of radiation by said projected acceptance geometry and having a major axis along said beam, means for directing said beam of said radiation through said sampling volume where it may impinge upon an object whose properties are to be measured, preseparator means for drawing a representative sample of ambient air containing the particulates to be weighed in a path crossing and normal to the major axis of the sampling volume, said receiver optics means including detector means for developing an analog signal related to the intensity of radiation directed onto said detector means and optical means for collecting and focusing onto said detector means radiation scattered from said sampling volume traversed by said beam and calibration/zero control means disposed between said sampling volume and the receiver optics means for periodically blocking said beam and redirecting a predetermined fraction of said beam onto said optical means and for periodically interrupting said scattered radiation such that said analog signal includes a plurality of time varying signal components including a calibration signal component, a zero signal component and a measurement signal component, means for processing said analog signal to develop individual control signals corresponding to said signal components for providing automatic compensation of the electro-optical system and means responsive to said analog signal for developing read out information corresponding to the mass concentration of the particulates in the sampling volume.

Claim 23

An electro-optical system for measurement of mass concentration of particulates in an open work area comprising a plurality of remote monitoring stations disposed at various locations in the work area, each location including a terminal box, means for connecting each said terminal box to an air source connected for air flow in both directions and for electrically connecting each said terminal box to a central control station, at least one electro-optical aerosol monitor supported adjacent a terminal box, means connecting said monitor through said terminal box to the air source and control station for operation thereof, each said monitor including a horizontally disposed electro-optical assembly and a vertically disposed preseparator having a central channel including a lower opening in communication with the open work area and an upper opening in communication with the air source through said terminal box, each said monitor comprising a source of substantially monochromatic electromagnetic radiation, optical means for directing a beam of said radiation through a sampling volume for impingement upon particulates contained therein whose mass concentration is to be measured, and receiver optics including photo detector means responsive to said radiation for developing an analog signal representative of radiation directed onto said detector means and indicative of the mass concentration of particulates in the sampling volume and optical means for collecting and directing radiation from said sampling volume traversed by said beam, said sampling volume being defined by the interception of the beam of radiation by the projected acceptance geometry of the optic receiver, and said channel of said preseparator being disposed along an axis intercepting said sample volume to allow a representative sample of air to flow across said sampling volume.

Claim 24

An electro-optical system for measurement of mass concentration of particulates in an open work area comprising a plurality of remote monitoring stations disposed at various locations in the work area, each location including a terminal box, means for connecting each said terminal box to an air source connected for air flow in both directions and for electrically connecting each said terminal box to a central control station, at least one electro-optical aerosol monitor supported adjacent a terminal box, means connecting said monitor through said terminal box to the air source and control station for operation thereof, each said monitor including a horizontally disposed electro-optical assembly and a vertically disposed preseparator having a central channel including a lower opening in communication with the open work area and an upper opening in communication with the air source through said terminal box, each said monitor comprising a source of substantially monochromatic electromagnetic radiation, optical means for directing a beam of said radiation through a sampling volume for impingement upon particulates contained therein whose mass concentration is to be measured, and receiver optics including photo detector means responsive to said radiation for developing an analog signal representative of radiation directed onto said detector means and indicative of the mass concentration of particulates in the sampling volume and optical means for collecting and directing radiation from said sampling volume traversed by said beam, said sampling volume being defined by the interception of the beam of radiation by the projected acceptance geometry of the optic receiver, and said channel of said preseparator being disposed along an axis intercepting said sample volume to allow a representative sample of air to flow across said sampling volume.

Claim 25

A system as set forth in claim 19 further including means connected to said photodetector means for classifying said analog signal according to whether small or large particulates are detected in the sampling volume and developed a classification signal in response thereto, means for sub-classifying said classification signal according to the size thereof and developing an output signal in response thereto and means for operating on said output signal to develop a read out of the mass concentration of the particulates in the sampling volume.

Claim 28

A system as set forth in claim 22 wherein said precipitator means for desiccating comprises a heater within the separator.

Claim 31

A system as defined in claim 25 wherein said calibration means is rotatably supported for positioning within the sampling volume and in the path of the beam of radiation.

Claim 32

A system as defined in claim 25 wherein said calibration means includes a plurality of calibration elements each adapted to be positioned in the sampling volume.

Claim 33

A system as defined in claim 27 wherein said calibration means is rotatable about an axis disposed to the side of the axis of the beam.

Claim 34

A system as defined in claim 27 wherein said axis is normal to the axis of the beam.

Claim 36

A system as defined in claim 18 or 19 further including means connected to said pre-separator, for causing particle free fluid to pass through the sampling volume.

Claim 37

A portable electro-optical air monitor for providing in situ measurements of the mass concentration of particulates entrained in air and adapted to be externally worn by a worker in the area in which the air is to be monitored comprising a housing, an electro-optical assembly within said housing including a source of substantially monochromatic electromagnetic radiation, optical means for directing a beam of said radiation through a sampling volume for impingement upon particulates and scattering of radiation from said particulates contained therein whose mass concentration is to be measured, and receiver optics including photo detector means responsive to scattered radiation for developing a signal representative of scattered radiation directed onto said detector means and indicative of the mass concentration of particulates in the sampling volume and processing said signal to develop an output corresponding to the mass concentration of the particulates in the sampling volume and optical means for collecting and directing radiation from said sampling volume traversed by said beam onto said photodetector, said sampling volume being defined by the interception of the beam of radiation by the projected acceptance geometry of the receiver optics, and said housing having a plurality of apertures on opposite sides of said sampling volume for drawing a representative sample of air across said sampling volume.

Claim 38

A portable electro-optical air monitor for providing in situ measurements of the mass concentration of particulates entrained in air and adapted to be externally worn by a worker in the area in which the air is to be monitored comprising a housing, an electro-optical assembly within said housing including a source of substantially monochromatic electromagnetic radiation, optical means for directing a beam of said radiation through a sampling volume for impingement upon particulates and scattering of radiation from said particulates contained therein whose mass concentration is to be measured, and receiver optics including photo detector means responsive to scattered radiation for developing a signal representative of scattered radiation directed onto said detector means and indicative of the mass concentration of particulates in the sampling volume and processing said signal to develop an output corresponding to the mass concentration of the particulates in the sampling volume and optical means for collecting and directing radiation from said sampling volume traversed by said beam onto said photodetector, said sampling volume being defined by the interception of the beam of radiation by the projected acceptance geometry of the receiver optics, and said housing having a plurality of apertures on opposite sides of said sampling volume for drawing a representative sample of air across said sampling volume.

Claim 39

A portable air monitor for providing in situ measurements of the mass concentration of particulates as set forth in claim 32 wherein said housing includes a removable cap at one end of said housing, a connector within said housing, said connector being accessible from exterior of said housing upon removal of said cap to allow excess to the data collected by said photodetector from an external source.

Claim 40

A monitor as set forth in claim 33 including a calibration element having a first stow position clear of the radiation beam and a second position in the path of said beam and in the sampling volume, and means for pivoting said element between the first and second positions.

Claim 41

A portable air monitor for electro-optically weighing, in situ, particulates entrained in air comprising a monitor housing adapted to be worn by a worker exposed to the air being monitored, said housing containing means for producing a beam of substantially monochromatic electromagnetic radiation, a sampling volume disposed between said means for producing said beam of radiation and receiver optic means having a radiation acceptance geometry whose projection intercepts said beam of radiation, said sampling volume being defined by the interception of said beam of radiation by said projected acceptance geometry and having a major axis along said beam, means within said housing for directing said beam of radiation through said sampling volume where it may impinge upon an object whose properties are to be measured, a plurality of openings on opposite sides of said housing and on opposite sides of the sampling volume for drawing ambient air containing the particulates to be weighed in a path crossing and normal to the major axis of the sampling volume, said receiver optics means including detector means for developing an analog signal related to the intensity of radiation directed onto said detector means and optical means for collecting and focusing onto said detector means radiation scattered from said sampling volume traversed by said beam and periodically blocking said beam and redirecting a predetermined fraction of said beam onto said optical means and for periodically interrupting said scattered radiation such that said analog signal includes a plurality of time varying signal components including a calibration signal component, a zero signal component and means connected to said detector for processing said analog signal to develop an output signal corresponding to the mass concentration of the particulates in the sampling volume.

Claim 42

A portable air monitor for electro-optically weighing, in situ, particulates entrained in air comprising a monitor housing adapted to be worn by a worker exposed to the air being monitored, said housing containing means for producing a beam of substantially monochromatic electromagnetic radiation, a sampling volume disposed between said means for producing said beam of radiation and receiver optic means having a radiation acceptance geometry whose projection intercepts said beam of radiation, said sampling volume being defined by the interception of said beam of radiation by said projected acceptance geometry and having a major axis along said beam, means within said housing for directing said beam of radiation through said sampling volume where it may impinge upon an object whose properties are to be measured, a plurality of openings on opposite sides of said housing and on opposite sides of the sampling volume for drawing ambient air containing the particulates to be weighed in a path crossing and normal to the major axis of the sampling volume, said receiver optics means including detector means for developing an analog signal related to the intensity of radiation directed onto said detector means and optical means for collecting and focusing onto said detector means radiation scattered from said sampling volume traversed by said beam and periodically blocking said beam and redirecting a predetermined fraction of said beam onto said optical means and for periodically interrupting said scattered radiation such that said analog signal includes a plurality of time varying signal components including a calibration signal component, a zero signal component and means connected to said detector for processing said analog signal to develop an output signal corresponding to the mass concentration of the particulates in the sampling volume.

Claim 43

A system as set forth in claim 35 wherein said means connected to said detector includes means for classifying said analog signal according to whether small or laarge particulates are detected in the sampling volume and developing a classification signal in response thereto, means for sub-classifying said classification signal according to the size thereof and developing an output signal in response thereto and means for operating on said output signal to develop a read out of the mass concentration of the particulates in the sampling volume.

Claim 46

A method as set forth in claim 37 wherein said convection currents are caused to occur by heating the representative sample of air.

Claim 47

A method as set forth in claim 37 wherein said step of drawing a sample of air includes restricting the flow of air across a predetermined cross sectional area defined in a plane normal to the direction of air flow and parallel to the beam.